Vacuum Advance

Does anyone know why my vacuum advance has 2 vacuum pipes?

One goes to the carb and one to the manifold is this better or worse than the standard one?

One is to provide advance, the other is to retard the timing during different throttle conditions.

Not a case of being "worse" as it does the job intended- to keep the timing as optimal as it can be, considering that its all purely mechanically done.

If its all working ok, then let it alone, you cant fix it if its not broken.
 

Overboost said

One is to provide advance, the other is to retard the timing during different throttle conditions.

Not a case of being "worse" as it does the job intended- to keep the timing as optimal as it can be, considering that its all purely mechanically done.

If its all working ok, then let it alone, you cant fix it if its not broken.
 

Ok just wondering if it was a valid mod or just someones left over junk, thanks

does any body know how much advance is needed whilst sorting out igniton timing mine is runing with 20 degrees of advance my son is training to be a mechanic and hass told me that there is 20 degrees advance on tick over but when under load it turns to top dead centre is this right ?

So far as I understand it it should only advance once the accelerator is pressed and more vacuum is created, at idle there should be no vacuum and so no advance.